Sieve all-purpose flour into a mixing bowl.

Add salt and baking soda to the flour.

In another bowl, combine unsalted butter and powdered sugar.

Beat butter and sugar together using a hand mixer until smooth.

Add egg and beat again until the mixture is soft and smooth.

Gradually add the dry flour mixture to the wet ingredients.

Add milk to the mixture and combine with a spatula.

Transfer the dough to a floured board and knead until smooth.

Roll out the dough and cut into 1/2 inch round shapes using a cookie cutter.

Place the roundels on a parchment paper on a baking sheet.

Bake in a preheated oven for 20 minutes, or until the edges turn golden.

Let cool on a wire rack before serving.